object: convert lookup_object() to use object_id

There are no callers left of lookup_object() that aren't just passing us
the "hash" member of a "struct object_id". Let's take the whole struct,
which gets us closer to removing all raw sha1 variables.  It also
matches the existing conversions of lookup_blob(), etc.

The conversions of callers were done by hand, but they're all mechanical
one-liners.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/name-rev.c

@@ -378,8 +378,7 @@ static void name_rev_line(char *p, struct name_ref_data *data)
 			*(p+1) = 0;
 			if (!get_oid(p - (hexsz - 1), &oid)) {
 				struct object *o =
-					lookup_object(the_repository,
-						      oid.hash);
+					lookup_object(the_repository, &oid);
 				if (o)
 					name = get_rev_name(o, &buf);
 			}